As helical polymers, there are known: a biological polymer which has asymmetric carbon in its polymer main chain, typical examples of which include deoxyribonucleic acid, ribonucleic acid, proteins, polypeptide, and polysaccharides; a synthetic polymer which has no asymmetric carbon in its polymer main chain but has asymmetric carbon in its side chain thereby causing the main chain to express a helical structure, examples of which include polyisocyanate, polysilane, polyisocyanide, and polyacetylene; and a synthetic polymer having a stereoregularity controlled in such a manner that its polymer main chain forms a helical structure, an example of which is isotactic vinyl polymer.
In recent years, research projects wherein biomimesis is a key word have been actively made. In particular, attention has been drawn to a helical structure formed by biological molecule, and energetic research and development efforts has been focused in synthetic polymers wherein a helical structure as described above having a function is formed.
It is stated that a polymer of optically active triphenylmethyl methacrylate disclosed in, e.g., Patent Document 1 has a helical structure, thereby having a high optical rotation, so that this compound itself is useful as an optical resolving agent.
Patent Document 2 discloses an optically active poly(meth)acrylamide compound. It is stated that this compound is useful as an adsorbent for separating a racemic mixture into optical enantiomers thereof for its asymmetric structure based on an optically active side chain of the compound.
Furthermore, Patent Document 3 states that: a salt of a poly(carboxyarylacetylene derivative) has a unique nature that it exhibits circular dichroism in a long wavelength range in water in the presence of an optically active amino acid or optically active amino alcohol; and the salt is useful as a chiral sensor or an optical resolving agent.
Patent Document 4 discloses a liquid crystalline composition using an optically active polymer compound.
Furthermore, as basic research, there is an example regarding polyisocyanate or polysilane having asymmetric carbon in its side chain wherein stiff rigid rod property of a helical structure formed by polymer main chain is used to function as a mesogen for expressing liquid crystallinity, and thus a stiff main chain type liquid crystal is expressed in an organic solvent or thermotropic system (Patent Document 5).
It is important to supply liquid crystallinity to a material since the material is useful as an optically functional polymer material and can be used in many industrial fields. The supply of liquid crystallinity can easily be attained regarding side chain type liquid crystals having a liquid crystal moiety in their side chain, and thus, many research examples have been reported. Also, with regard to polyacetylene which is a typical example of an electroconductive polymer to which particular attention has been paid in recent years, a side chain type liquid crystal is reported (Patent Document 6).
Although nucleic acid or a polysaccharide expresses a liquid crystal structure in a dense aqueous solution, there is no case wherein a synthetic helical polymer as described above expresses a stiff main chain type liquid crystal in a aqueous solution thereof from the viewpoint of biomimetic material or in basic research.
Hitherto, commencing with Patent Document 3 and so on, various chiral sensors have been disclosed. However, in industrial fields, a material having a chiral discrimination with a still higher sensitivity has been desired.    Patent Document 1: JP-A-56-106907    Patent Document 2: JP-A-63-1446    Patent Document 3: JP-A-2001-294625    Patent Document 4: JP-A-1-79230    Patent Document 5: JP-A-2001-164251    Patent Document 6: JP-A-2-227425    Patent Document 7: JP-A-9-176243    Patent Document 8: JP-A-2001-294626    Patent Document 9: JP-A-2001-294626    Patent Document 10: JP-A-2003-55410    Patent Document 11: JP-A-2003-292538